Major Electrical Woes-Help (long post)

[John F.]

Crows Nest has Detroit 8.2 dry-turbo (over the road) motors that were marinized by J&T (Capt. Pat referred to them as "junk and trash"--I get it). The boat was rewired before Doug got it, and the wiring job is not well done. Actually, it just sucks. The wire looks OK, but the connectors are basic RadioShack type connectors and they're crimped without solder or shrink stuff or tape. She's had electrical gremlins for years--since I've known her. She has 2 batteries, and two battery switches that have "1," "2," "combination," "off" positions. She's never started on "1" or "2" regardless of charge, and so the switches were just left on "combination." The gauges seemed to read fine, although the starboard motor oil pressure always seemed to read high. If she wasn't plugged into shore power, and the switches were left on, the batteries would be dead in a few days. If she was left plugged into shore power, the zincs would go quickly. My solution was to turn the battery switches to "off" after using the boat and not leave her plugged in. That worked.

I replaced the switches a year or so ago because they were all corroded, and just wired them the same as they were without thinking. This past winter I started the rewire by moving the batteries and battery switches from outside the starboard motor to outside the port motor. This corrected the list she had from removing the starboard side "westerbroke" (also Capt. Pat) generator that was always broken (and heavy). When I removed the switches I remember thinking that they didn't seem to be wired correctly--"1" didn't go to "1" on the other switch, or something like that.

I got her together this spring, and took her out for a shakedown. The starboard motor voltmeter wouldn't go over "10," the starboard oil pressure gauge again seemed to read high (80 psi at cold idle, 45 psi or so at hot idle), and starboard water temp that usually settled at around 160 went up to 180, then shot to 240 as I was looking at the gauge. I immediately throttled to idle and the gauge went back to 180. So, I went home to try to figure this out. DD 8.2s don't react well to overheats, and if that motor had gotten that hot, it'd probably be done. I've seem motors overheat, and the motor didn't seem hot. Plus, I haven't seen a motor gain and lose 60 degrees in a matter of seconds. But, I'm no mechanic either, that's for sure.

The port motor stuff works fine. The port motor will spin, run, and the gauges will read properly when the port motor battery switch is on "1," "2," or combination. I thought I had an overheat problem on the starboard motor and went through everything. I had my wife run the boat while I had my trusty laser heat gun, and got the same readings (all fine) on both motors in the same places. The starboard water temp gauge did the same thing--went to 180, shot to 240 (my wife screamed), brought it back it idle and the gauge went back to 180, but the temp of the motor was fine. If you keep her under 2000 rpms, the gauge will stay around 180. Go over that and the gauge starts to climb, then it'll shoot to 240. The voltmeter still won't go over "10," and oil pressure reads high. I'm convinced I don't have an overheat problem. I've gone through everything, and laser heat gun checked everything multiple times.

Checking things out, the starboard motor will spin but not start when its battery switch is on "1" (no fuel I'm guessing, and you can't hear the "click" of the fuel solenoid), and do nothing on "2." It'll start and run fine on "combination," but the water temp gauge reads high (like 180 up to 240 when the laser gun shows none of that), and the oil pressure gauge still seems to read high. I put a voltmeter on the alternator output, and it reads 13.5. The battery reads 13.5, but the voltmeter gauge on the dash is right--it reads 10, and I get 10 when I put the voltmeter on the positive of the gauge.

The starters have 2 solenoids on the top of the starters per starter. I'm guessing that the aft solenoid, because of the way its wired, does something for the starter circuit. The forward solenoid I'm guessing does something for fuel. The wiring to the solenoids on top of the starters is slightly different motor to motor. The starboard motor forward solenoid had one less wire. I found the same color "red" wire as on the port motor (just about every wire is red or black, which sucks) disconnected and tied back. When I connected it to the solenoid so it matched the wiring on the port motor, it tripped the starboard motors main breaker thing under the dash. So, I disconnected it.

She runs fine, but I think its pretty clear that something is very wrong in the wiring. I didn't know that a wiring problem can cause the gauges to misread. Any advice as to what to look for? I'm planning on a rewire (especially now) for my next winter project, but I'd like to run the boat this summer. Any idea what's going on? My electrical wiring experience/talent/knowledge is severely limited. I can usually at least figure out what's going on, but electrical stuff has me stumped. This is torturing me

Thanks-

John

[ranjr13]

John - I'm not an electrical wizard, but here's what I'd do to get through the summer. First, you did the most important thing, confirm that it's not truly an overheat issue with the laser. Second, if you are not comfortable that the boat was wired properly, isolate only the most important things you will need to use it, and add from there. In other words, disconnect the batteries, wire the disconnects and bilge pump(s) with fuses, then start from there. Trace every wire going to the engine controls and gauges, and power nothing else. If gauges and controls appear to be a mess, I'd even consider getting a couple separate pressure and temp gauges, wire up a remote panel just to get by, and use that for the summer. Once you have engines and all of their supporting equipment working properly, then you could add one or two other items, perhaps just on a temporary basis with their own fuse and power path, avoiding any panel that might be a rats nest.

I know you want to use it, but as is it's probably a fire waiting to start. I would not leave plugged in if you don't trust it. My panel was nice when the boat was refurbished 20 years ago - there are 2 panels waiting for me to install this coming winter, both relocating them and updating. Luckily I don't have the gremlins you do, or mine would be out of the water with batteries out of it for the rest of the season.

Best of luck, please share how you make out.

Bob

[Carl]

John-
Far from an electrical person...but what I tend to do when something works on one motor and not the other. I copy whats on the working side. As to temp gauge I'd be swapping the sensors or swapping the leads across motors to narrow down the culprit.

Just a guess...if sensor is good, temp gauge jumping up quick and dropping just as quick might be some juice coming in from another wire leaking voltage that gets energized at high rpm's, or vibration creates a connection...you did mention lousy connections.

But to be honest...you have alot of things going on all at once. In a case like that I'd be over my head and grab me a good marine electrician/mechanic and pay them well to go to town. Or at least pay them to sort out you required systems and disconnect everything else till you have the time to tackle it as a whole. Fire and stray currents are not something you want on a boat. A funky guage or a switch or two is one thing...

Sorry, not much help...or at least not the help you wanted I know.

[CamB25]

John,

Sounds like you have a combination of bad grounds and high resistance connections, along with mysterious battery wiring, questionable gauges, and who knows what type of wire. Fun! Try to simplify as much as possible for the season. If you need a hand, you can borrow my brain and body for a day (note: both are long past the warranty date), along with all my electrical tools. I have the gigantic battery lug crimper, small crimpers, soldering irons, heat guns, etc. Just let me know.

Cam

[John F.]

Thanks for the replies. Cam--I may take you up on your offer. I need to find some time to just trace wires and see what goes where. Once I figure out what's going where, then maybe I can copy the port motor's wiring.

[John F.]

This mess turned out to be a bunch of bad and missing grounds. Had a friend/mechanic go over stuff with me, and he gave me a "to do" list. I did it, got stuff cleaned up, and ran a couple of new grounds, and the battery switches and gauges work fine.

[Dug]

John,

I just read your post and all of the following ones.

I am really glad to hear the gremlins have been put off.

Dug